Synchronization of Content Between Networked Devices

1. A media playback system comprising: a first control device comprising: a first network interface configured to wirelessly communicate using a first communication protocol; a first user interface configured to detect user input from a uccr; at least one first processor; at least one first non-transitory computer-readable medium; and first program instructions stored on the at least one first non-transitory computer-readable medium that are executable by the at least one first processor such that the first control device is configured to: after receipt of a command to initiate playback of media content via the first user interface, transmit at least one message to a video playback device based on the command via the first network interface, wherein the media content comprises visual content and audio content associated with the visual content; the video playback device comprising: a second network interface configured to wirelessly communicate using the first communication protocol; a third network interface configured to communicate using a second communication protocol that is different from the first communication protocol; at least one second processor; at least one second non-transitory computer-readable medium; and second program instructions stored on the at least one second non-transitory computer-readable medium that are executable by the at least one second processor such that the video playback device is configured to: join a synchrony group with at least one audio playback device; receive, via the second network interface, the at least one message from the first control device; obtain, via the third network interface, the media content based on the at least one message; determine an indication of when to begin playback of the media content; transmit, via the third network interface, the indication of when to begin playback of the media content to the at least one audio playback device; based on the indication of when to begin playback of the media content, output the media content in synchrony with playback of the audio content by the at least one audio playback device; and while the media content is output in synchrony with playback of the audio content by the at least one audio playback device, transmit, via the third network interface, timing information to the at least one audio playback device to cause the at least one playback device to modify playback of the audio content to maintain synchrony with playback of the media content by the video playback device; wherein transmission of the timing information comprises transmission of at least one packet comprising an indication of when to play back at least one of a plurality of sections of the audio content; and a second control device comprising: a second user interface configured to detect user input; at least one third processor; at least one third non-transitory computer-readable medium; and third program instructions stored on the at least one third non-transitory computer-readable medium that are executable by the at least one third processor such that the second control device is configured to: receive, via the second user interface, a command to modify the synchrony group; and cause the synchrony group to be modified based on the received command to modify the synchrony group.

2. The media playback system of claim 1 , wherein the second program instructions that are executable by the at least one second processor such that the video playback device is configured to transmit timing information to the at least one audio playback device comprises program instructions that are executable by the at least one second processor such that the video playback device is configured to transmit timing information to the at least one audio playback device to cause the at least one audio device to modify a playback rate of the audio content to maintain synchrony with playback of the media content by the video playback device.

3. The media playback system of claim 1 , wherein the second program instructions that are executable by the at least one second processor such that the video playback device is configured to transmit timing information to the at least one audio playback device comprises program instructions that are executable by the at least one second processor such that the video playback device is configured to transmit timing information to the at least one audio playback device to cause the at least one audio playback device to modify a local clock rate.

4. The media playback system of claim 1 , wherein the third program instructions that are executable by the at least one third processor such that the second control device is configured to cause the synchrony group to be modified comprises program instructions that are executable by the at least one third processor such that the second control device is configured to transmit at least one message to the video playback device.

5. The media playback system of claim 4 , wherein the second program instructions that are executable by the at least one second processor such that the video playback device is configured to join the synchrony group with the at least one audio playback device comprises program instructions that are executable by the at least one second processor such that the video playback device is configured to join the synchrony group with the at least one audio playback device based on the at least one message from the second control device.

6. The media playback system of claim 1 , wherein the audio content comprises a plurality of frames and wherein the second program instructions that are executable by the at least one second processor such that the video playback device is configured to transmit the timing information comprises program instructions that are executable by the at least one second processor such that the video playback device is configured to transmit at least one packet comprising an amount of time until playback of at least one of the plurality of frames.

7. The media playback system of claim 1 , wherein the audio content comprises a plurality of frames and wherein the second program instructions that are executable by the at least one second processor such that the video playback device is configured to transmit the timing information comprises program instructions that are executable by the at least one second processor such that the video playback device is configured to transmit at least one packet comprising a presentation timestamp for at least one of the plurality of frames.

8. The media playback system of claim 1 , wherein the video playback device further comprises program instructions that are executable by the at least one second processor such that the video playback device is configured to determine a network latency for a connection between the video playback device and the at least one audio playback device and wherein the second program instructions that are executable by the at least one second processor such that the video playback device is configured to determine the indication of when to begin playback of the media content comprises program instructions that are executable by the at least one second processor such that the video playback device is configured to determine the indication of when to begin playback of the media content based on the determined network latency.

9. The media playback system of claim 8 , wherein the program instructions that are executable by the at least one second processor such that the video playback device is configured to determine the indication of when to begin playback of the media content comprises program instructions that are executable by the at least one second processor such that the video playback device is configured to: send a test packet to the at least one audio playback device at a first time based on a local clock of the video playback device; receive an acknowledgement packet from the at least one audio playback device at a second time based on the local clock of the video playback device; determine a test packet delay calculation based on a difference between the second time and the first time; and determine the network latency based on the test packet delay calculation.

10. The media playback system of claim 1 , wherein the at least one audio playback device comprises a first playback device and wherein the playback system further comprises the first playback device.

11. The media playback system of claim 10 , wherein the first playback device comprises: a fourth network interface configured to communicate using the second communication protocol; an audio amplifier; a speaker coupled to the audio amplifier; at least one fourth processor; at least one fourth non-transitory computer-readable medium; and fourth program instructions stored on the at least one fourth non-transitory computer-readable medium that are executable by the at least one fourth processor such that the first playback device is configured to: receive, via the fourth network interface, the indication of when to begin playback of the media content from the video playback device; based on the indication of when to begin playback of the media content, play back the associated audio content in synchrony with the video playback device using the audio amplifier and the speaker; and while playing back the associated audio content in synchrony with playback of the media content by the video playback device, after receipt of timing information from the video playback device via the fourth network interface, modify playback of the audio content based on the timing information.

12. The media playback system of claim 1 , wherein the video playback device is a television comprising a display and wherein the program instructions that are executable by the at least one second processor such that the video playback device is configured to output the media content comprise program instructions that are executable by the at least one second processor such that the video playback device is configured to display the visual content on the display.

13. A method performed by media playback system comprising a first control device, a second control device, and a video playback device, the method comprising: receiving, via a user interface of the first control device, a command to initiate playback of media content, wherein the media content comprises visual content and audio content associated with the visual content; transmitting, via a network interface of the first control device using a first communication protocol, at least one message to a video playback device based on the command; receiving, via a first network interface of the video playback device using the first communication protocol, the at least one message from the first control device; obtaining, via a second network interface of the video playback device using a second communication protocol that is different from the first communication protocol, the media content based on the at least one message; determining, using the video playback device, an indication of when to begin playback of the media content; transmitting, via the second network interface of the video playback device, the indication of when to begin playback of the media content to at least one audio playback device that is in a synchrony group with the video playback device; based on the indication of when to begin playback of the media content, outputting, using the video playback device, the visual content in synchrony with playback of the associated audio content by the at least one audio playback device; while outputting the visual content in synchrony with playback of the associated audio content by the at least one audio playback device, transmitting, via the second network interface of the video playback device, timing information to the at least one audio playback device to maintain synchrony with playback of the associated audio content by the at least one audio playback device, wherein transmitting the timing information comprises transmitting at least one packet comprising an indication of when to play back at least one of a plurality of sections of the media content; receiving, via a user interface of the second control device, a command to modify the synchrony group; and causing, via the second control device, the synchrony group to be modified based on the received command to modify the synchrony group.

14. The method of claim 13 , wherein the audio content comprises a plurality of frames and wherein transmitting the least one packet comprising the indication of when to play back the at least one of the plurality of sections of the audio content comprises: transmitting, via the video playback device to the at least one audio playback device, at least one packet comprising an amount of time until playback of at least one of the plurality of frames.

15. The method of claim 13 , wherein the audio content comprises a plurality of frames and wherein transmitting the least one packet comprising the indication of when to play back at least one of the plurality of sections of the audio content comprises transmitting, via the video playback device to the at least one audio playback device, at least one packet comprising a presentation timestamp for at least one of the plurality of frames.

16. A media playback system comprising: a video playback device comprising: a first network interface configured to wirelessly communicate over at least one wireless local area network (WLAN) using a first communication protocol; a second network interface configured to wirelessly communicate using a second communication protocol that is different from the first communication protocol; at least one first processor; at least one first non-transitory computer-readable medium; and first program instructions stored on the at least one first non-transitory computer-readable medium that are executable by the at least one first processor such that the video playback device is configured to: join a synchrony group with an audio playback device; after receipt of a command to initiate playback of media content via the second network interface from a first control device, obtain the media content based on the command via the second network interface, wherein the media content comprises visual content and audio content associated with the visual content; determine an indication of when to begin playback of the media content; transmit, via the first network interface, the indication of when to begin playback of the media content to the audio playback device; based on the indication of when to begin playback of the media content, output the media content in synchrony with playback of the audio content by the audio playback device; while the media content is output in synchrony with playback of the audio content by the audio playback device, transmit, via the first network interface, timing information to the audio playback device to maintain synchrony with playback of the media content by the video playback device, wherein transmission of the timing information comprises transmission of at least one packet comprising an indication of when to play back at least one of a plurality of sections of the audio content; receive, from a second control device via the first network interface, a command to modify the synchrony group; and modify the synchrony group based on the received command to modify the synchrony group; and the audio playback device comprising: a third network interface configured to wirelessly communication over at least one wireless local area network (WLAN); an audio amplifier; a speaker coupled to the audio amplifier; at least one second processor; at least one second non-transitory computer-readable medium; and second program instructions stored on the at least one second non-transitory computer-readable medium that are executable by the at least one second processor such that the audio playback device is configured to: after receipt of the indication of when to begin playback of the media content from the video playback device via the third network interface, play back the associated audio content in synchrony with the video playback device using the audio amplifier and the speaker based on the indication of when to begin playback of the media content; and while playing back the associated audio content in synchrony with playback of the visual content by the video playback device, after receipt of timing information from the video playback device via the third network interface, modify playback of the audio content based on the timing information.

17. The media playback system of claim 16 , wherein the second program instructions that are executable by the at least one second processor such that the audio playback device is configured to modify playback of the audio content comprises program instructions that are executable by the at least one second processor such that the audio playback device is configured to: modify a playback rate of the audio content based on the timing information.

18. The media playback system of claim 17 , wherein the second program instructions that are executable by the at least one second processor such that the audio playback device is configured to modify the playback rate of the audio content comprise program instructions that are executable by the at least one second processor such that the audio playback device is configured to: modify a local clock based on the timing information.